Time of the month can be a sprain as well as a pain

Monday 12 February 2007 23:07 BST

Pain: Menstrual cycle can weaken muscles and ligaments

The menstrual cycle of women has been blamed for many things, most notably severe mood swings and irritability but, according to one experienced osteopath, the ebb and flow of hormones could also make women more vulnerable to injuring themselves.

Studying his female patients, Dr Stephen Sandler concluded that fluctuating levels of oestrogen and relaxin can weaken muscles and ligaments, increasing the risk of problems.

He pointed to two pressure points in an average 28-day cycle when the likelihood is greatest.

In the middle, women experience a dramatic drop in oestrogen, which gives strength to muscles and ligaments, and are more susceptible to back or pelvic strain.

Then, at around days 24 to 26, levels of the hormone relaxin rise in readiness for the start of the next period, which can lead to problems in the lower back and neck.

Dr Sandler, an osteopath for more than 25 years who is based at the Portland Hospital, said: 'I noted men often came to me with injuries due to sport or over-exertion.

'But women often couldn't explain why simple acts like reaching down to pick something up had caused injury and pain.'

He studied 17 women after noticing that female patients were coming to see him at specific times of their cycle and then surveyed 1,000 fellow osteopaths.

'I found this experience repeated and that these women were hurting

themselves at certain points in their cycle,' said Dr Sandler.

'There was a clear link between hormone levels and laxity of joints making women more vulnerable to injury.

'As they progress through their cycle, their joints become increasingly loose.'

It is hoped the intriguing discovery could help women, especially athletes who need to avoid injury, to adapt their schedules to cut the risk of hurting themselves.

Rebecca Morrison, from the British School of Osteopathy, said: 'These results will be valuable to women and health professionals.

'Studies have shown that female athletes and those engaged in recreational sport were more prone to injury at certain times and now we understand why.

'This is significant for women everywhere who can plan their schedules around their cycles and avoid potentially painful injuries.

'It will also aid therapists in the rehabilitation of their patients.'

Typically, 20 per cent of women reported pain at days 12 to 14 of their cycle and 17 per cent at days 24 to 26.

These are the days when oestrogen drops or relaxin is released.

'At both these stages, women are more susceptible to strains and damage,' said Dr Sandler.

By the end of the cycle, when menstruation starts, normal joint strength returned.

However, women taking the combined contraceptive pill should not experience the same problems as their oestrogen levels are kept relatively constant.